A magnetic storage device typically comprises one or more magnetic disks, each having at least one data recording surface including a plurality of concentric tracks of magnetically stored data, means such as a spindle motor for supporting and rotating the disk(s), at least one read/write transducer per recording surface for reading information from and writing information to the recording surface, an air bearing slider for supporting the transducer over the recording surface, and means such as an actuator/suspension assembly for selectively positioning the transducer and slider over a desired data track.
As is generally known in the art, airflow enters the slider's leading edge and flows in the direction of its trailing edge, generating a lifting force or "positive pressure" on the slider's air bearing surface (ABS), thereby supporting the slider at a nominal fly height over the recording surface.
As is also known in the art, numerous air bearing designs exist to achieve particular fly height characteristics. Many of these designs include air bearing designs that provide openings to the incoming airflow. A problem with such designs occurs when debris enters these openings and becomes trapped between the ABS and the recording surface. Particles may occur, for example, during the manufacture or assembly of the disk drive, from moving parts that wear over a period of time, a faulty air filtering system, or slider contact with disk asperities. If the particles are small, they will merely pass beneath the ABS unobstructed. However, larger particles of debris will be trapped, for example, by encountering obstructing features such as cross rails, or by becoming jammed between the slider and disk as the particles move toward the trailing edge, where slider-to-disk spacing decreases. As a result, the trapped debris can scratch the recording surface, and can damage the delicate transducer or interfere with its operation. It is therefore desirable to prevent large particles from passing between the ABS and recording surface by providing some means for diverting them away from the operating slider.
A number of design approaches have been taken to deal with surface debris. For example, U.S. Pat. No. 4,212,044 discloses a positive pressure slider with an air bearing surface comprising a pair of side rails and a plurality of shaped diverter blades at the trailing edge and parallel to the incoming airflow. The diverter blades force small particles of dust to either side, preventing the accumulation of dust along the trailing edge. However, this design will not prevent larger particles from passing beneath the ABS and becoming trapped at the trailing edge.
U.S. Pat. No. 5,210,666 discloses a negative pressure slider with a notch formed in its tapered cross-rail, functioning in part to minimize debris collection at the slider's leading edge. Rather than preventing particles from passing beneath the ABS, this design permits relatively small particles to pass under the ABS so that they do not accumulate at the leading edge. As is generally known in the art, a negative pressure slider design includes a region for generating a suction force to counteract and stabilize the positive pressure on the ABS.
Japanese application no. 4-228157 discloses a negative pressure slider having two T-shaped rails defining a negative pressure cavity with a shallow groove opening to the leading edge. The groove provides a channel for debris so that it does pass beneath the slider and therefore does not accumulate along the leading edge.
IBM Technical Disclosure Bulletin Vol. 35, No. 7, page 14, December 1992 discloses a slider for use in a rotary actuator disk drive, including a skewed rail for sweeping aside particles on the disk surface. This design is useful for pushing aside particles too large to pass beneath the slider ABS, but would not prevent all large particles from lodging between the slider and recording surface.
what is needed is a debris diverting means for an air bearing slider operating in contaminated disk drive environments, thereby avoiding damage to the slider, its transducer, and the recording surface of a magnetic disk drive by preventing large particles from passing under the slider's ABS to its trailing edge. Preferably, the diverter would not significantly affect the fly height characteristics of the slider, so that the same diverter could be used for a variety of ABS designs. Also needed is a relatively simple fabrication process for implementing diverting means on a slider.